1 00:00:02,233 --> 00:00:05,602 >> Earth, a 4.5 billion year old 2 00:00:05,703 --> 00:00:09,773 Planet, still evolving. 3 00:00:09,841 --> 00:00:11,975 As continents shift and clash, 4 00:00:12,043 --> 00:00:15,745 volcanoes erupt, glaciers grow 5 00:00:15,780 --> 00:00:18,482 and recede, the Earth's crust is 6 00:00:18,516 --> 00:00:20,383 carved in countless, fascinating 7 00:00:20,418 --> 00:00:22,419 ways, leaving a trail of 8 00:00:22,520 --> 00:00:26,690 geological mysteries behind. 9 00:00:26,757 --> 00:00:29,759 This is the story of Hawaii, a 10 00:00:29,861 --> 00:00:31,394 mountain chain over 80 million 11 00:00:31,496 --> 00:00:33,230 years old and home to the 12 00:00:33,331 --> 00:00:35,232 most active volcano in the 13 00:00:35,333 --> 00:00:38,468 world. 14 00:00:38,503 --> 00:00:39,970 In this exquisite, volatile 15 00:00:40,037 --> 00:00:41,872 landscape, scientists hunt for 16 00:00:41,939 --> 00:00:42,973 clues to the islands' 17 00:00:43,040 --> 00:00:46,309 origins - clues that may shed 18 00:00:46,377 --> 00:00:48,512 new light on the formation of 19 00:00:48,579 --> 00:00:52,653 the Earth itself. S01x12 Hawaii Original Air Date on May 5, 2009 20 00:00:52,654 --> 00:00:56,654 21 00:00:56,754 --> 00:00:58,922 Hawaii. The most isolated group 22 00:00:58,956 --> 00:01:01,057 of islands on Earth, stretching 23 00:01:01,125 --> 00:01:03,393 1,500 miles across the middle of 24 00:01:03,461 --> 00:01:06,196 the Pacific Ocean. 25 00:01:06,230 --> 00:01:07,931 These eight tropical islands are 26 00:01:07,965 --> 00:01:09,399 one of the youngest geological 27 00:01:09,467 --> 00:01:12,135 formations on the planet. 28 00:01:12,236 --> 00:01:14,504 With stunning beaches, huge 29 00:01:14,572 --> 00:01:16,673 canyons and the biggest 30 00:01:16,741 --> 00:01:20,677 volcanoes on Earth, this is 31 00:01:20,778 --> 00:01:26,483 where paradise meets hell. 32 00:01:26,584 --> 00:01:28,051 The investigation into how 33 00:01:28,119 --> 00:01:31,688 Hawaii was formed began in 1934. 34 00:01:31,756 --> 00:01:34,658 Dutch geophysicist Felix Meinesz 35 00:01:34,759 --> 00:01:36,560 invented the gravimeter, an 36 00:01:36,594 --> 00:01:38,195 incredible machine which enabled 37 00:01:38,229 --> 00:01:39,729 scientists to accurately measure 38 00:01:39,764 --> 00:01:43,867 gravity for the first time. 39 00:01:43,935 --> 00:01:44,935 With his cutting-edge 40 00:01:45,002 --> 00:01:46,736 technology, Meinesz was able to 41 00:01:46,804 --> 00:01:48,104 calculate the gravitational 42 00:01:48,172 --> 00:01:50,173 forces at work on the Big Island 43 00:01:50,274 --> 00:01:51,908 and, using this data, determine 44 00:01:51,976 --> 00:01:55,612 its size. 45 00:01:55,646 --> 00:01:57,080 His results revealed that the 46 00:01:57,148 --> 00:01:58,815 Big Island was like a gigantic 47 00:01:58,883 --> 00:02:00,917 iceberg. Only its tip was 48 00:02:00,985 --> 00:02:02,986 visible above the ocean. But 49 00:02:03,054 --> 00:02:04,354 drain away the water and its 50 00:02:04,455 --> 00:02:06,923 true size is remarkable. The 51 00:02:06,991 --> 00:02:08,258 island is twice the height of 52 00:02:08,359 --> 00:02:09,893 Everest, and so massive that 53 00:02:09,994 --> 00:02:12,896 Everest could fit inside it 140 54 00:02:12,964 --> 00:02:19,436 times. 55 00:02:19,537 --> 00:02:21,071 Geologist Mike Poland heads to 56 00:02:21,105 --> 00:02:22,239 the top of the mountain Mauna 57 00:02:22,306 --> 00:02:24,040 Kea, the highest point on the 58 00:02:24,108 --> 00:02:25,775 Big Island, to get a sense of 59 00:02:25,843 --> 00:02:29,980 its true enormity. 60 00:02:30,047 --> 00:02:31,047 >> We're standing at the top of 61 00:02:31,148 --> 00:02:33,149 Mauna Kea volcano, which is the 62 00:02:33,217 --> 00:02:34,417 tallest mountain in the world. 63 00:02:34,518 --> 00:02:37,320 It's 13,796 feet above sea 64 00:02:37,421 --> 00:02:39,656 level, but it goes all the way 65 00:02:39,690 --> 00:02:40,790 down to the ocean floor and 66 00:02:40,858 --> 00:02:42,759 ends up being about 56,000 feet 67 00:02:42,793 --> 00:02:45,495 high. 68 00:02:45,596 --> 00:02:47,030 >> This giant island is the 69 00:02:47,098 --> 00:02:49,099 largest in the United States and 70 00:02:49,166 --> 00:02:50,100 bigger than all the other 71 00:02:50,201 --> 00:02:53,570 Hawaiian Islands put together. 72 00:02:53,638 --> 00:02:55,705 Intrigued, scientists set out to 73 00:02:55,740 --> 00:02:57,107 discover what could have created 74 00:02:57,208 --> 00:03:01,911 such a huge land mass. 75 00:03:02,013 --> 00:03:03,747 10,000 feet below the peak of 76 00:03:03,848 --> 00:03:05,749 Mauna Kea and 70 miles to the 77 00:03:05,816 --> 00:03:07,984 south, the prime suspect is 78 00:03:08,019 --> 00:03:11,888 plain to see - the awesome 79 00:03:11,922 --> 00:03:15,091 Kilauea volcano. 80 00:03:15,159 --> 00:03:16,092 >> (Poland) We like to call 81 00:03:16,160 --> 00:03:17,060 Kilauea the most active volcano 82 00:03:17,161 --> 00:03:18,094 in the world because it's been 83 00:03:18,162 --> 00:03:19,562 erupting continuously since 84 00:03:19,630 --> 00:03:21,931 1983. And it's been going every 85 00:03:21,999 --> 00:03:23,566 day, almost nonstop, since that 86 00:03:23,634 --> 00:03:26,703 time. Since early 2008, it's 87 00:03:26,737 --> 00:03:27,837 been even more active, 'cause 88 00:03:27,905 --> 00:03:28,838 now we have this summit 89 00:03:28,906 --> 00:03:29,973 eruption as well, so now 90 00:03:30,007 --> 00:03:32,375 Kilauea's perhaps by two times 91 00:03:32,476 --> 00:03:33,643 the most active volcano in the 92 00:03:33,711 --> 00:03:36,279 world. 93 00:03:36,380 --> 00:03:37,914 >> But this volcano is not 94 00:03:37,982 --> 00:03:40,283 predictable. Although the summit 95 00:03:40,384 --> 00:03:42,552 is no longer spewing out lava, 96 00:03:42,653 --> 00:03:44,521 12 miles down on the south flank 97 00:03:44,555 --> 00:03:46,623 of the volcano is an active 98 00:03:46,657 --> 00:03:52,796 vent. 99 00:03:52,830 --> 00:03:55,465 For the last 25 years, lava has 100 00:03:55,533 --> 00:03:56,966 been gushing out of the side of 101 00:03:57,001 --> 00:03:59,102 the volcano from this vent, 102 00:03:59,170 --> 00:04:06,109 with no signs of stopping. 103 00:04:06,177 --> 00:04:08,712 Homes, towns and forests are 104 00:04:08,746 --> 00:04:10,447 swallowed up by scorching hot 105 00:04:10,514 --> 00:04:15,018 lava. With each new flow, layer 106 00:04:15,086 --> 00:04:16,720 upon layer of black crust 107 00:04:16,787 --> 00:04:18,621 builds, covering the island in 108 00:04:18,723 --> 00:04:22,826 volcanic rock. 109 00:04:22,893 --> 00:04:24,994 Could this huge island have been 110 00:04:25,096 --> 00:04:29,432 built entirely by lava? 111 00:04:29,467 --> 00:04:30,800 Experts needed to figure out 112 00:04:30,901 --> 00:04:32,969 exactly how much lava Kilauea 113 00:04:33,003 --> 00:04:36,272 produces. Their first clue can 114 00:04:36,374 --> 00:04:39,075 be found all over the volcano. 115 00:04:39,143 --> 00:04:41,544 Clinging to the rocks are yellow 116 00:04:41,612 --> 00:04:44,280 crystals. These are sulfur 117 00:04:44,348 --> 00:04:46,316 crystals and tell scntists 118 00:04:46,417 --> 00:04:48,017 that Kilauea volcano is 119 00:04:48,052 --> 00:04:49,686 releasing vast amounts of 120 00:04:49,787 --> 00:04:53,323 sulfur dioxide gas. 121 00:04:53,424 --> 00:04:55,024 To determine just how much the 122 00:04:55,059 --> 00:04:56,593 volcano is producing, 123 00:04:56,694 --> 00:04:58,128 researchers take regular 124 00:04:58,229 --> 00:05:00,497 measurements. 125 00:05:00,598 --> 00:05:02,766 >> The amount of sulfur dioxide 126 00:05:02,867 --> 00:05:05,068 that effervesces from the magma 127 00:05:05,136 --> 00:05:06,970 is tied directly to the amount 128 00:05:07,037 --> 00:05:08,405 of magma that's coming out of 129 00:05:08,506 --> 00:05:09,506 the ground, the amount of lava 130 00:05:09,607 --> 00:05:11,775 that's erupted. So by measuring 131 00:05:11,876 --> 00:05:13,410 the amount of sulfur dioxide, 132 00:05:13,477 --> 00:05:15,779 we can use that number to 133 00:05:15,880 --> 00:05:17,781 calculate how much lava is being 134 00:05:17,882 --> 00:05:20,283 erupted. 135 00:05:20,351 --> 00:05:21,818 >> These samples reveal 136 00:05:21,919 --> 00:05:25,522 staggering results. 137 00:05:25,556 --> 00:05:27,824 Kilauea could be producing 100 138 00:05:27,892 --> 00:05:29,826 million cubic yards of lava a 139 00:05:29,894 --> 00:05:32,729 year, more than any volcano on 140 00:05:32,797 --> 00:05:35,064 Earth. But there isn't this much 141 00:05:35,099 --> 00:05:37,333 lava flowing across the surface. 142 00:05:37,368 --> 00:05:39,969 So where does the rest of it go? 143 00:05:40,004 --> 00:05:42,172 Geologists ventured below the 144 00:05:42,273 --> 00:05:44,140 surface, into the guts of the 145 00:05:44,175 --> 00:05:48,044 volcano, to investigate. 146 00:05:48,078 --> 00:05:49,712 Stretching 400 feet into the 147 00:05:49,780 --> 00:05:51,981 dark is a strange tunnel, just 148 00:05:52,082 --> 00:05:54,584 like a subway tunnel. But it's 149 00:05:54,652 --> 00:05:57,487 not a manmade structure. It's 150 00:05:57,555 --> 00:05:59,756 part of a vast network of tubes 151 00:05:59,824 --> 00:06:01,624 that hold the key to how much 152 00:06:01,659 --> 00:06:05,094 lava moves around the island. 153 00:06:05,129 --> 00:06:06,196 >> We're standing in Thurston 154 00:06:06,297 --> 00:06:07,764 lava tube in Hawaii Volcanoes 155 00:06:07,832 --> 00:06:09,299 National Park, and this lava 156 00:06:09,366 --> 00:06:10,300 tube was one of the main 157 00:06:10,367 --> 00:06:12,035 conduits for lava that was 158 00:06:12,102 --> 00:06:13,203 flowing from Kilauea summit 159 00:06:13,304 --> 00:06:14,938 to the sea in an eruption that 160 00:06:15,005 --> 00:06:17,106 occurred about 500 years ago. 161 00:06:17,208 --> 00:06:18,475 So once this tube system has 162 00:06:18,576 --> 00:06:19,576 been established, you 163 00:06:19,643 --> 00:06:20,743 essentially have an underground 164 00:06:20,811 --> 00:06:22,645 river of lava. So these tube 165 00:06:22,746 --> 00:06:24,180 systems can be very long-lived 166 00:06:24,215 --> 00:06:25,281 and very efficient delivery 167 00:06:25,349 --> 00:06:29,185 systems for lava. 168 00:06:29,253 --> 00:06:31,287 >> The lava is so hot it burns a 169 00:06:31,388 --> 00:06:32,822 channel into the rocks beneath 170 00:06:32,923 --> 00:06:35,758 it. 171 00:06:35,826 --> 00:06:37,527 This incredible time-lapse 172 00:06:37,561 --> 00:06:39,095 footage shows that, because the 173 00:06:39,163 --> 00:06:41,030 top of the flow is still exposed 174 00:06:41,098 --> 00:06:43,199 to the air, it cools and crusts 175 00:06:43,300 --> 00:06:47,103 over. Below this crust, a tunnel 176 00:06:47,171 --> 00:06:48,638 forms, through which the lava 177 00:06:48,739 --> 00:06:51,941 continues to flow. 178 00:06:52,009 --> 00:06:53,910 But how much lava can these 179 00:06:53,978 --> 00:06:59,115 tubes carry? 180 00:06:59,183 --> 00:07:01,017 Back on the surface, Dr. Ken Hon 181 00:07:01,118 --> 00:07:02,652 is carefully inspecting the lava 182 00:07:02,720 --> 00:07:06,422 fields to find an active tube. 183 00:07:06,490 --> 00:07:08,324 Only inches beneath his feet 184 00:07:08,359 --> 00:07:10,627 could be a tunnel full of 2,000 185 00:07:10,694 --> 00:07:15,398 degree lava. 186 00:07:15,432 --> 00:07:16,900 Dr. Hon is on the look out for a 187 00:07:16,967 --> 00:07:19,135 skylight, a window in the 188 00:07:19,236 --> 00:07:21,471 ceiling of a tube. They can come 189 00:07:21,505 --> 00:07:22,772 and go within days and are a 190 00:07:22,840 --> 00:07:24,641 sure sign of an active lava 191 00:07:24,675 --> 00:07:25,842 tube. 192 00:07:25,910 --> 00:07:27,577 >> You can see the lava glowing 193 00:07:27,678 --> 00:07:29,846 inside the lava tube. This one's 194 00:07:29,947 --> 00:07:31,481 about ten to 15 feet wide and 195 00:07:31,582 --> 00:07:33,550 probably about five feet deep. 196 00:07:33,584 --> 00:07:35,184 And it's about 2,000 degrees 197 00:07:35,219 --> 00:07:36,920 Fahrenheit, and it glows like 198 00:07:36,954 --> 00:07:39,222 the sun. 199 00:07:39,290 --> 00:07:40,757 >> These hidden tunnels keep the 200 00:07:40,858 --> 00:07:42,859 lava insulated and hot, 201 00:07:42,927 --> 00:07:44,227 preventing it from cooling and 202 00:07:44,295 --> 00:07:46,129 turning into solid rock, 203 00:07:46,196 --> 00:07:47,931 enabling it to travel further 204 00:07:47,998 --> 00:07:49,566 and faster than lava on the 205 00:07:49,667 --> 00:07:51,834 surface. 206 00:07:51,936 --> 00:07:53,202 >> What we're looking at is on 207 00:07:53,304 --> 00:07:55,004 the order of about five cubic 208 00:07:55,039 --> 00:07:56,639 yards every second going 209 00:07:56,674 --> 00:07:58,808 in this lava tube underneath us. 210 00:07:58,842 --> 00:08:00,577 And that's the equivalent of 211 00:08:00,678 --> 00:08:02,478 about a dump truck worth of lava 212 00:08:02,546 --> 00:08:03,846 every two seconds, so if I was 213 00:08:03,948 --> 00:08:04,948 standing on the freeway, what 214 00:08:05,015 --> 00:08:06,215 you would see is one dump truck 215 00:08:06,283 --> 00:08:07,750 after another dump truck after 216 00:08:07,818 --> 00:08:09,552 another dump truck going by me 217 00:08:09,587 --> 00:08:11,220 here, transporting a phenomenal 218 00:08:11,288 --> 00:08:14,657 amount of material. 219 00:08:14,758 --> 00:08:16,359 >> Hundreds of these expressways 220 00:08:16,393 --> 00:08:18,261 crisscross the island, carrying 221 00:08:18,295 --> 00:08:20,997 lava underground up to 30 miles 222 00:08:21,031 --> 00:08:22,665 until it reaches its inevitable 223 00:08:22,733 --> 00:08:26,069 destination... 224 00:08:26,170 --> 00:08:41,451 the ocean. 225 00:08:41,518 --> 00:08:43,786 And when 2,000 degree lava meets 226 00:08:43,821 --> 00:08:45,355 seawater, the results are 227 00:08:45,422 --> 00:08:55,798 spectacular. 228 00:08:55,899 --> 00:08:58,134 This interaction is key to how 229 00:08:58,168 --> 00:08:59,869 the Big Island was created and 230 00:08:59,903 --> 00:09:02,805 is continually growing. 231 00:09:02,873 --> 00:09:04,707 >> When the lava hits the ocean, 232 00:09:04,808 --> 00:09:07,877 it's extremely hot and it 233 00:09:07,978 --> 00:09:09,178 shatters into lots of little 234 00:09:09,246 --> 00:09:10,947 pieces, so what it does is leave 235 00:09:10,981 --> 00:09:14,984 a lot of black sand behind it. 236 00:09:15,052 --> 00:09:16,719 >> Layer upon layer of this 237 00:09:16,787 --> 00:09:18,888 black sandy rubble slowly piles 238 00:09:18,989 --> 00:09:20,723 up on the ocean floor until it 239 00:09:20,791 --> 00:09:24,260 forms a new beach. 240 00:09:24,328 --> 00:09:26,162 New lava on the surface runs 241 00:09:26,230 --> 00:09:27,964 across this beach, cooling 242 00:09:28,065 --> 00:09:29,699 slowly to form a new piece 243 00:09:29,800 --> 00:09:31,434 of solid land on sandy 244 00:09:31,502 --> 00:09:35,338 foundations. This massive island 245 00:09:35,439 --> 00:09:37,440 is built on piles of loose 246 00:09:37,508 --> 00:09:39,308 rubble. 247 00:09:39,343 --> 00:09:40,443 >> We're looking right here at 248 00:09:40,511 --> 00:09:41,811 the process by which the 249 00:09:41,879 --> 00:09:45,148 Hawaiian Islands grow. 250 00:09:45,215 --> 00:09:46,416 >> The Big Island is the fastest 251 00:09:46,517 --> 00:09:48,351 growing piece of land on Earth, 252 00:09:48,419 --> 00:09:50,420 as lava from Kilauea adds 20 253 00:09:50,521 --> 00:09:52,055 football fields a year to its 254 00:09:52,122 --> 00:09:54,991 already colossal size. But this 255 00:09:55,059 --> 00:09:57,960 just isn't enough. More lava is 256 00:09:58,028 --> 00:09:59,162 needed to build this huge 257 00:09:59,229 --> 00:10:01,164 Island, so just where is it 258 00:10:01,231 --> 00:10:03,166 coming from? The clues are in 259 00:10:03,233 --> 00:10:05,301 the landscape itself. While 260 00:10:05,335 --> 00:10:07,170 Kilauea forms only one peak on 261 00:10:07,237 --> 00:10:08,705 the island, four other 262 00:10:08,806 --> 00:10:10,440 megastructures tower over the 263 00:10:10,507 --> 00:10:14,510 landscape. 264 00:10:14,578 --> 00:10:15,678 >> Over a million years ago, 265 00:10:15,713 --> 00:10:16,946 there was no Big Island of 266 00:10:16,980 --> 00:10:18,681 Hawaii. It started as a very 267 00:10:18,782 --> 00:10:20,149 small island, which was the 268 00:10:20,217 --> 00:10:21,784 volcano of Kohala, which grew 269 00:10:21,885 --> 00:10:23,519 out of the ocean. Over time, 270 00:10:23,620 --> 00:10:25,154 more volcanoes started to grow, 271 00:10:25,255 --> 00:10:26,789 Mauna Kea and Hualalai came 272 00:10:26,890 --> 00:10:28,324 next, growing into tremendous 273 00:10:28,392 --> 00:10:29,959 Mountains. Mauna Loa was the 274 00:10:30,060 --> 00:10:31,427 next volcano to grow. And 275 00:10:31,528 --> 00:10:32,862 Kilauea is the youngest of the 276 00:10:32,930 --> 00:10:36,365 Big Island's volcanoes. 277 00:10:36,400 --> 00:10:38,134 >> Over a million years, lava 278 00:10:38,202 --> 00:10:40,303 from these five volcanoes slowly 279 00:10:40,404 --> 00:10:42,105 built the Big Island up from the 280 00:10:42,206 --> 00:10:45,108 sea floor. The biggest island in 281 00:10:45,175 --> 00:10:47,210 the United States is one big 282 00:10:47,311 --> 00:10:56,285 volcanic rock. 283 00:10:56,386 --> 00:10:57,987 The mystery of how Hawaii was 284 00:10:58,021 --> 00:11:00,189 made is slowly unraveling as the 285 00:11:00,257 --> 00:11:01,924 evidence emerges from its fiery 286 00:11:01,992 --> 00:11:05,728 volcanoes. Experiments in the 287 00:11:05,796 --> 00:11:07,363 1930s revealed that the Big 288 00:11:07,431 --> 00:11:09,365 Island is a vast structure, 289 00:11:09,433 --> 00:11:11,067 stretching three miles down to 290 00:11:11,135 --> 00:11:13,903 the sea floor. Readings of 291 00:11:13,971 --> 00:11:15,805 sulfur dioxide gas show that 292 00:11:15,873 --> 00:11:17,807 Kilauea produces more lava than 293 00:11:17,908 --> 00:11:21,544 any other volcano on Earth. 294 00:11:21,612 --> 00:11:23,613 The landscape reveals that lava 295 00:11:23,714 --> 00:11:25,615 from five volcanoes built the 296 00:11:25,716 --> 00:11:28,684 Island. 297 00:11:28,719 --> 00:11:30,453 The Big Island of Hawaii is a 298 00:11:30,521 --> 00:11:32,421 stunning wilderness dominated by 299 00:11:32,523 --> 00:11:35,091 fire and destruction. But what 300 00:11:35,159 --> 00:11:36,726 force on Earth could create the 301 00:11:36,794 --> 00:11:38,594 most active volcano in the 302 00:11:38,629 --> 00:11:41,164 world, 2,000 miles from the 303 00:11:41,265 --> 00:11:43,166 nearest land, in the middle of 304 00:11:43,233 --> 00:11:47,503 the Pacific? 305 00:11:52,257 --> 00:11:54,125 Hawaii is filled with evidence 306 00:11:54,192 --> 00:11:58,095 of a volcanic past. 307 00:11:58,196 --> 00:11:59,663 The eight islands are made up 308 00:11:59,731 --> 00:12:02,933 of 15 mammoth volcanoes. 309 00:12:03,034 --> 00:12:05,102 Molokai boasts two huge 310 00:12:05,203 --> 00:12:07,071 mountains, the Big Island is 311 00:12:07,105 --> 00:12:08,906 dominated by the giant Mauna 312 00:12:08,940 --> 00:12:11,809 Loa, and in Honolulu, houses are 313 00:12:11,843 --> 00:12:13,978 crowded around the now extinct 314 00:12:14,012 --> 00:12:16,213 Diamond Head crater. 315 00:12:16,314 --> 00:12:18,349 Geologists had figured out that 316 00:12:18,450 --> 00:12:19,950 the Big Island was created by 317 00:12:19,985 --> 00:12:22,520 five volcanoes. Next, they 318 00:12:22,621 --> 00:12:24,321 wanted to know how the entire 319 00:12:24,356 --> 00:12:29,994 chain had come into existence. 320 00:12:30,061 --> 00:12:32,329 7,000 miles away, off the coast 321 00:12:32,397 --> 00:12:33,964 of Indonesia, is the mighty 322 00:12:34,065 --> 00:12:40,538 Krakatoa. 323 00:12:40,605 --> 00:12:43,040 Ever since it exploded in 1883, 324 00:12:43,108 --> 00:12:44,575 scientists have been trying to 325 00:12:44,676 --> 00:12:46,310 understand the forces that 326 00:12:46,378 --> 00:12:51,282 create volcanoes. 327 00:12:51,316 --> 00:12:53,284 Experts plotted all the active 328 00:12:53,318 --> 00:12:55,386 volcanoes in the world on a map, 329 00:12:55,453 --> 00:12:56,754 and an extraordinary fact 330 00:12:56,821 --> 00:13:00,925 emerged. 80 percent lay around 331 00:13:01,026 --> 00:13:03,561 the edge of the Pacific Ocean. 332 00:13:03,662 --> 00:13:05,396 This long line of volcanoes 333 00:13:05,497 --> 00:13:07,031 became known as the Ring of 334 00:13:07,098 --> 00:13:12,002 Fire. 452 giant volcanoes make 335 00:13:12,037 --> 00:13:13,737 up the ring, and it is thought 336 00:13:13,772 --> 00:13:15,206 that eruptions began in this 337 00:13:15,307 --> 00:13:24,014 area over 36 million years ago. 338 00:13:24,082 --> 00:13:26,850 During the 1950s and '60s, a 339 00:13:26,918 --> 00:13:28,319 theory emerged that finally 340 00:13:28,386 --> 00:13:30,020 began to make sense of these 341 00:13:30,121 --> 00:13:32,456 fire mountains. Geologists 342 00:13:32,490 --> 00:13:33,857 realized that the Earth's crust 343 00:13:33,925 --> 00:13:35,659 was made up of eight major and 344 00:13:35,760 --> 00:13:37,561 many minor plates, fitting 345 00:13:37,662 --> 00:13:39,096 together like a giant jigsaw 346 00:13:39,130 --> 00:13:40,397 puzzle. 347 00:13:40,465 --> 00:13:42,032 >> They move relative to one 348 00:13:42,133 --> 00:13:43,033 another, sometimes they 349 00:13:43,101 --> 00:13:44,101 intersect, sometimes they 350 00:13:44,135 --> 00:13:46,370 diverge. These plate boundaries 351 00:13:46,404 --> 00:13:47,805 are where we see most geologic 352 00:13:47,839 --> 00:13:50,474 activity. For example, along the 353 00:13:50,542 --> 00:13:51,909 Pacific Ring of Fire, where 354 00:13:51,943 --> 00:13:52,943 there's lots of volcanoes and 355 00:13:53,011 --> 00:13:55,279 earthquakes, that marks plate 356 00:13:55,313 --> 00:13:58,115 boundary locations. 357 00:13:58,216 --> 00:13:59,483 >> The theory was called 358 00:13:59,584 --> 00:14:02,219 subduction. When tectonic plates 359 00:14:02,287 --> 00:14:04,021 collide, the heavier oceanic 360 00:14:04,122 --> 00:14:05,623 plate is forced down into the 361 00:14:05,657 --> 00:14:07,858 Earth's intensely hot interior, 362 00:14:07,926 --> 00:14:10,394 taking water with it. The water 363 00:14:10,462 --> 00:14:12,029 forces magma to swirl up and 364 00:14:12,097 --> 00:14:13,397 push through the plate, where it 365 00:14:13,465 --> 00:14:17,668 forms volcanoes. 366 00:14:17,736 --> 00:14:19,270 But when geologists looked at 367 00:14:19,304 --> 00:14:21,038 the volcanoes of Hawaii, it was 368 00:14:21,106 --> 00:14:23,674 clear the theory didn't fit. 369 00:14:23,742 --> 00:14:25,209 They couldn't have been created 370 00:14:25,277 --> 00:14:26,844 as the plates collided, because 371 00:14:26,911 --> 00:14:28,846 they sit 2,000 miles from the 372 00:14:28,913 --> 00:14:35,085 nearest boundary. 373 00:14:35,120 --> 00:14:36,120 >> Here in Hawaii, we're in the 374 00:14:36,187 --> 00:14:37,288 middle of a plate, so we 375 00:14:37,355 --> 00:14:38,555 wouldn't expect to see that much 376 00:14:38,657 --> 00:14:40,391 activity. That's another bit of 377 00:14:40,458 --> 00:14:41,558 evidence that there's got to be 378 00:14:41,660 --> 00:14:43,193 some anomaly here that's 379 00:14:43,261 --> 00:14:44,461 causing all of the melting we 380 00:14:44,529 --> 00:14:45,896 see in the middle of this large 381 00:14:45,930 --> 00:14:48,299 plate. 382 00:14:48,366 --> 00:14:50,100 >> Puzzled, geologists decided 383 00:14:50,168 --> 00:14:51,302 to look at the volcanoes of 384 00:14:51,369 --> 00:14:52,803 Hawaii in the hope they might 385 00:14:52,837 --> 00:14:54,738 give up their secrets. But all 386 00:14:54,839 --> 00:14:55,939 they found were more 387 00:14:56,007 --> 00:14:59,109 differences. Most of the world's 388 00:14:59,210 --> 00:15:00,844 volcanoes are cone-shaped, with 389 00:15:00,912 --> 00:15:02,479 steep sides many thousands of 390 00:15:02,547 --> 00:15:04,815 feet tall, but Hawaii's 391 00:15:04,916 --> 00:15:06,550 volcanoes look completely 392 00:15:06,651 --> 00:15:09,887 different. 393 00:15:09,921 --> 00:15:11,088 >> We call these volcanoes 394 00:15:11,189 --> 00:15:12,289 shield volcanoes because of 395 00:15:12,357 --> 00:15:13,924 their shape. If you're looking 396 00:15:14,025 --> 00:15:15,092 behind me at Mauna Loa, it's 397 00:15:15,193 --> 00:15:17,461 got these very smooth sloping 398 00:15:17,562 --> 00:15:18,662 flanks, it's like a warrior's 399 00:15:18,730 --> 00:15:19,730 shield that's been put on its 400 00:15:19,798 --> 00:15:23,100 end. 401 00:15:23,201 --> 00:15:24,735 >> Digging deeper, geologists 402 00:15:24,836 --> 00:15:26,370 decided to test the lava and 403 00:15:26,471 --> 00:15:28,005 found that Hawaiian volcanoes 404 00:15:28,106 --> 00:15:29,640 produce a distinct type of 405 00:15:29,708 --> 00:15:32,810 lava called basalt. Basalt lava 406 00:15:32,911 --> 00:15:34,278 is made of rocks which have been 407 00:15:34,346 --> 00:15:36,814 heated up to 2,000 degrees. 408 00:15:36,915 --> 00:15:38,282 Not only is it the hottest lava 409 00:15:38,383 --> 00:15:40,084 in the world, it's also some of 410 00:15:40,185 --> 00:15:41,719 the most fluid, and this makes 411 00:15:41,820 --> 00:15:44,822 it terrifyingly unpredictable. 412 00:15:44,923 --> 00:15:46,724 >> (man) We gotta get outta here! 413 00:15:46,791 --> 00:15:49,426 Get outta here! 414 00:15:49,461 --> 00:15:50,561 >> The lava that erupts here in 415 00:15:50,628 --> 00:15:52,629 Hawaii is very runny, it's much 416 00:15:52,731 --> 00:15:54,631 runnier than the kind of lavas 417 00:15:54,699 --> 00:15:55,632 that erupt from places like 418 00:15:55,700 --> 00:15:56,633 Mount Rainier or Mount St. 419 00:15:56,701 --> 00:15:59,203 Helens, which is much stickier. 420 00:15:59,270 --> 00:16:00,804 It's like comparing honey to 421 00:16:00,839 --> 00:16:03,707 toothpaste. 422 00:16:03,742 --> 00:16:04,975 >> It's this difference in the 423 00:16:05,009 --> 00:16:06,543 consistency of the lava that 424 00:16:06,611 --> 00:16:08,178 gives Hawaii's volcanoes their 425 00:16:08,246 --> 00:16:10,914 dramatically different shape. 426 00:16:11,015 --> 00:16:12,149 >> The sides of the volcanoes 427 00:16:12,217 --> 00:16:14,251 here are gently sloping because 428 00:16:14,319 --> 00:16:15,586 those lava flows can just run 429 00:16:15,620 --> 00:16:19,523 out as they need to. 430 00:16:19,591 --> 00:16:21,125 And the lava flows at places 431 00:16:21,159 --> 00:16:22,159 like Mount Rainier and Mount St. 432 00:16:22,227 --> 00:16:24,161 Helens, being very sticky, stay 433 00:16:24,229 --> 00:16:25,162 close to the volcano and build 434 00:16:25,230 --> 00:16:26,864 up very steep-sided volcanic 435 00:16:26,931 --> 00:16:35,973 cones. 436 00:16:36,040 --> 00:16:37,341 >> Geologists had uncovered 437 00:16:37,409 --> 00:16:39,243 crucial evidence, but they still 438 00:16:39,344 --> 00:16:40,978 did not understand what kind of 439 00:16:41,045 --> 00:16:43,213 force could create volcanoes in 440 00:16:43,248 --> 00:16:45,315 the middle of a plate 2,000 441 00:16:45,417 --> 00:16:51,054 miles from the nearest boundary. 442 00:16:51,156 --> 00:16:52,589 But whatever that force turned 443 00:16:52,690 --> 00:16:54,324 out to be, it would have to be 444 00:16:54,426 --> 00:16:56,960 enormous. Big enough to quite 445 00:16:57,061 --> 00:17:00,063 literally move a mountain. At 446 00:17:00,131 --> 00:17:01,498 the summit of the Big Island's 447 00:17:01,599 --> 00:17:03,867 Kilauea volcano, Dr. Mike Poland 448 00:17:03,968 --> 00:17:05,569 is using sophiicated global 449 00:17:05,637 --> 00:17:07,571 positioning equipment to measure 450 00:17:07,639 --> 00:17:12,209 changes in the volcano's size. 451 00:17:12,277 --> 00:17:14,178 >> G.P.S. is a tool for locating 452 00:17:14,212 --> 00:17:15,479 yourself anywhere on the surface 453 00:17:15,547 --> 00:17:16,980 of the Earth. You may be 454 00:17:17,015 --> 00:17:18,248 familiar with this from seeing 455 00:17:18,283 --> 00:17:19,750 G.P.S. units in cars. This is a 456 00:17:19,818 --> 00:17:21,385 different type of G.P.S., it's 457 00:17:21,453 --> 00:17:22,920 much more accurate. And that 458 00:17:22,987 --> 00:17:24,288 allows us to see how the ground 459 00:17:24,389 --> 00:17:25,722 is moving in centimeter-level 460 00:17:25,757 --> 00:17:27,391 scales. 461 00:17:27,459 --> 00:17:28,926 >> This cutting-edge technology 462 00:17:29,027 --> 00:17:30,661 is crucial to scientists in 463 00:17:30,728 --> 00:17:32,095 their struggle to understand the 464 00:17:32,163 --> 00:17:35,666 forces working beneath Hawaii. 465 00:17:35,767 --> 00:17:36,733 >> So we've got this G.P.S. 466 00:17:36,801 --> 00:17:38,702 setup here, we also have a 467 00:17:38,736 --> 00:17:40,370 G.P.S. setup on the far side of 468 00:17:40,438 --> 00:17:41,905 the aldera. Now, by looking at 469 00:17:41,973 --> 00:17:43,340 how the distance between those 470 00:17:43,374 --> 00:17:44,842 G.P.S. stations is changing, we 471 00:17:44,909 --> 00:17:45,843 can get an idea of whether or 472 00:17:45,910 --> 00:17:47,711 not the volcano is inflating or 473 00:17:47,745 --> 00:17:49,012 deflating. If it's inflating 474 00:17:49,113 --> 00:17:50,614 like a balloon, it means that 475 00:17:50,648 --> 00:17:51,615 there's magma that's 476 00:17:51,649 --> 00:17:52,616 accumulating beneath the 477 00:17:52,650 --> 00:17:54,451 surface, and if it's deflating, 478 00:17:54,552 --> 00:17:55,519 it may mean that there's magma 479 00:17:55,553 --> 00:17:56,987 that's leaving the subsurface. 480 00:17:57,021 --> 00:17:58,288 And over the past years, 481 00:17:58,356 --> 00:17:59,356 actually, these stations have 482 00:17:59,390 --> 00:18:00,557 gotten farther apart from one 483 00:18:00,625 --> 00:18:02,659 another by almost a foot. The 484 00:18:02,727 --> 00:18:04,461 kind of force necessary to 485 00:18:04,529 --> 00:18:06,096 inflate the volcano, to spread 486 00:18:06,164 --> 00:18:07,998 the Caldera wider by one foot, 487 00:18:08,099 --> 00:18:09,533 is tremendous, and it's a very 488 00:18:09,567 --> 00:18:10,968 good sign of magmahat's 489 00:18:11,035 --> 00:18:12,169 accumulating beneath the surface 490 00:18:12,237 --> 00:18:13,170 and may be getting ready to 491 00:18:13,238 --> 00:18:21,612 erupt. 492 00:18:21,679 --> 00:18:23,313 >> Evidence was mounting that a 493 00:18:23,348 --> 00:18:25,249 huge and unexplained force was 494 00:18:25,316 --> 00:18:28,318 at work beneath the chain. The 495 00:18:28,419 --> 00:18:29,887 volcanoes of Hawaii do not 496 00:18:29,954 --> 00:18:31,588 emerge from a plate boundary, 497 00:18:31,623 --> 00:18:33,323 but rise up right in the middle 498 00:18:33,424 --> 00:18:36,426 of the Pacific plate. Hawaii's 499 00:18:36,528 --> 00:18:38,128 Lava is dramatically different 500 00:18:38,162 --> 00:18:39,663 to that produced by the rest of 501 00:18:39,764 --> 00:18:42,432 the volcanoes in the Pacific. 502 00:18:42,500 --> 00:18:43,867 The islands of Hawaii were a 503 00:18:43,935 --> 00:18:46,236 thorn in the side of geology. 504 00:18:46,304 --> 00:18:47,571 But, although they remained an 505 00:18:47,605 --> 00:18:49,506 unexplained mystery, geologists 506 00:18:49,607 --> 00:18:52,042 weren't about to give up. And 507 00:18:52,110 --> 00:18:53,610 the answers they would find were 508 00:18:53,678 --> 00:18:55,112 so incredible that the debate 509 00:18:55,146 --> 00:18:57,314 they created still rages to this 510 00:18:57,382 --> 00:18:58,564 day. 511 00:19:02,995 --> 00:19:04,428 The puzzle of what created the 512 00:19:04,463 --> 00:19:05,830 Islands of Hawaii seemed 513 00:19:05,897 --> 00:19:09,433 impossible to solve. 514 00:19:09,468 --> 00:19:11,102 The mystery only deepened when, 515 00:19:11,169 --> 00:19:13,337 in the 1950s, the U.S. Navy 516 00:19:13,372 --> 00:19:14,638 mapped the ocean floor with 517 00:19:14,740 --> 00:19:19,076 sonar. 518 00:19:19,177 --> 00:19:20,544 They revealed a series of 519 00:19:20,645 --> 00:19:22,346 underwater mountains, known as 520 00:19:22,414 --> 00:19:24,348 Seamounts, that extended far 521 00:19:24,416 --> 00:19:25,916 beyond the chain of eight 522 00:19:25,984 --> 00:19:28,586 Hawaiian Islands. 523 00:19:28,620 --> 00:19:30,187 >> To the northwest are a whole 524 00:19:30,255 --> 00:19:32,256 string of sea mountains we call 525 00:19:32,324 --> 00:19:34,091 Seamounts. Those are sunken 526 00:19:34,192 --> 00:19:36,460 volcanic mountains, many of them 527 00:19:36,528 --> 00:19:38,462 with reefs on top of them. 528 00:19:38,530 --> 00:19:40,431 >> Over 80 seamounts and 19 529 00:19:40,532 --> 00:19:42,466 islands form this sequence, 530 00:19:42,534 --> 00:19:44,168 known as the Hawaiian-Emperor 531 00:19:44,236 --> 00:19:46,370 Seamount chain. 532 00:19:46,438 --> 00:19:47,371 >> (Blay) You're looking at a 533 00:19:47,439 --> 00:19:49,073 total distance from the Big 534 00:19:49,174 --> 00:19:51,776 Island of Hawaii out to Midway 535 00:19:51,810 --> 00:19:53,978 and all the way up to Russia of 536 00:19:54,046 --> 00:19:56,914 about 3,200 miles, it's one of 537 00:19:56,982 --> 00:19:58,349 the longest mountain chains in 538 00:19:58,450 --> 00:20:00,451 the world, but very little of it 539 00:20:00,519 --> 00:20:07,892 is above sea level. 540 00:20:07,993 --> 00:20:10,995 >> In 1963, Canadian geologist 541 00:20:11,063 --> 00:20:12,730 J. Tuzo wilson turned his 542 00:20:12,798 --> 00:20:14,065 attentions to the Hawaiian 543 00:20:14,132 --> 00:20:17,501 Islands. 544 00:20:17,536 --> 00:20:18,903 He was struck by the fact that 545 00:20:19,004 --> 00:20:20,538 both the Hawaiian Islands and 546 00:20:20,639 --> 00:20:22,606 Seamounts form a straight line 547 00:20:22,641 --> 00:20:23,974 that courses through the middle 548 00:20:24,076 --> 00:20:27,344 of the Pacific. 549 00:20:27,412 --> 00:20:28,979 Straight lines are incredibly 550 00:20:29,047 --> 00:20:31,315 rare in nature, they don't occur 551 00:20:31,349 --> 00:20:34,452 by accident, especially not a 552 00:20:34,519 --> 00:20:37,888 line over 3,000 miles long. 553 00:20:37,989 --> 00:20:39,990 Wilson believed that one single 554 00:20:40,092 --> 00:20:41,692 force must have created this 555 00:20:41,726 --> 00:20:43,327 vast chain of volcanic 556 00:20:43,361 --> 00:20:48,966 Islands and Seamounts. 557 00:20:49,000 --> 00:20:51,068 Wilson also made a very simple 558 00:20:51,169 --> 00:20:52,870 and yet incredibly astute 559 00:20:52,904 --> 00:20:54,905 deduction. The further the 560 00:20:54,973 --> 00:20:56,340 Islands of Hawaii were from the 561 00:20:56,441 --> 00:20:58,042 Big Island, the greener they 562 00:20:58,110 --> 00:21:01,212 got. And for Wilson, greener 563 00:21:01,313 --> 00:21:04,582 meant older. He noticed that the 564 00:21:04,649 --> 00:21:06,283 landscape on the Big Island is 565 00:21:06,318 --> 00:21:08,586 like a black desert, a barren 566 00:21:08,653 --> 00:21:09,854 wilderness with only a few 567 00:21:09,955 --> 00:21:11,021 seedlings peeping through the 568 00:21:11,089 --> 00:21:14,959 lava. Fresh lava flows regularly 569 00:21:15,026 --> 00:21:16,927 scorch the Earth, killing any 570 00:21:16,962 --> 00:21:20,297 plant life. 571 00:21:20,365 --> 00:21:22,133 But move north along the chain, 572 00:21:22,200 --> 00:21:23,300 and the islands become 573 00:21:23,401 --> 00:21:26,637 increasingly green. Wilson 574 00:21:26,671 --> 00:21:28,105 believed that on each successive 575 00:21:28,140 --> 00:21:30,107 Island, more time has passed 576 00:21:30,142 --> 00:21:31,842 since the last eruption, 577 00:21:31,943 --> 00:21:36,313 allowing more plants to grow. 578 00:21:36,381 --> 00:21:38,048 Two years later, using 579 00:21:38,116 --> 00:21:39,650 radiometric techniques, 580 00:21:39,684 --> 00:21:41,118 scientists dated rock samples 581 00:21:41,186 --> 00:21:43,120 from each of the islands. 582 00:21:43,188 --> 00:21:44,855 Their results confirmed Wilson's 583 00:21:44,956 --> 00:21:46,023 hunch and proved that the 584 00:21:46,091 --> 00:21:56,100 Islands increased in age. 585 00:21:56,134 --> 00:21:57,835 Dr. Poland has been collecting 586 00:21:57,903 --> 00:21:59,203 some of these rock samples and 587 00:21:59,271 --> 00:22:00,538 has brought them to the Big 588 00:22:00,572 --> 00:22:03,641 Island. 589 00:22:03,675 --> 00:22:04,642 >> This rock right here is from 590 00:22:04,676 --> 00:22:05,643 the lava flow that we're 591 00:22:05,677 --> 00:22:07,111 standing on, this is one of the 592 00:22:07,179 --> 00:22:08,379 youngest rocks on the island. 593 00:22:08,480 --> 00:22:09,480 And, in fact, we could go and 594 00:22:09,548 --> 00:22:10,848 pick up some lava that formed 595 00:22:10,882 --> 00:22:16,587 yesterday if it weren't too hot. 596 00:22:16,655 --> 00:22:17,655 If we move down to the middle of 597 00:22:17,756 --> 00:22:19,290 the chain, we get this rock here 598 00:22:19,391 --> 00:22:21,292 which is from Oahu, and this is 599 00:22:21,359 --> 00:22:22,359 about three and a half million 600 00:22:22,394 --> 00:22:27,298 years old. 601 00:22:27,365 --> 00:22:28,732 This rock here is from a lava 602 00:22:28,767 --> 00:22:30,401 flow on the island of Kauai, 603 00:22:30,468 --> 00:22:31,468 It's from the island that's the 604 00:22:31,536 --> 00:22:33,270 farthest away from where we are 605 00:22:33,305 --> 00:22:34,939 today on the Big Island. You 606 00:22:35,006 --> 00:22:37,074 notice how dull it is, that's 607 00:22:37,108 --> 00:22:38,209 because it is very old, it's 608 00:22:38,310 --> 00:22:45,816 about five million years old. 609 00:22:45,850 --> 00:22:47,017 >> Wilson pulled together 610 00:22:47,118 --> 00:22:48,485 evidence from rock dating and 611 00:22:48,553 --> 00:22:50,187 the straight line forged by the 612 00:22:50,288 --> 00:22:51,922 Islands and came up with a 613 00:22:51,990 --> 00:22:54,658 single theory. He proposed that 614 00:22:54,726 --> 00:22:56,393 Hawaii was created by something 615 00:22:56,461 --> 00:22:58,162 called a hotspot, an 616 00:22:58,196 --> 00:22:59,930 exceptionally hot region beneath 617 00:23:00,031 --> 00:23:01,665 the Earth's crust that was 618 00:23:01,733 --> 00:23:03,200 concentrated under Hawaii's 619 00:23:03,301 --> 00:23:06,370 Big Island. As the pacific plate 620 00:23:06,471 --> 00:23:08,372 moved slowly over this hotspot, 621 00:23:08,440 --> 00:23:09,740 the immense heat punched 622 00:23:09,808 --> 00:23:11,075 through the crust to form a 623 00:23:11,109 --> 00:23:14,912 chain of volcanic islands. 624 00:23:15,013 --> 00:23:16,647 >> So this hot spot is a--a 625 00:23:16,748 --> 00:23:18,382 constant and stationary source 626 00:23:18,450 --> 00:23:19,917 of heat beneath the Earth's 627 00:23:20,018 --> 00:23:21,752 surface, it's like a blowtorch 628 00:23:21,820 --> 00:23:23,120 pointed up at the surface of the 629 00:23:23,188 --> 00:23:24,655 Earth. And as the Earth's 630 00:23:24,723 --> 00:23:25,656 surface moves over that 631 00:23:25,757 --> 00:23:27,992 blowtorch, it punches through, 632 00:23:28,026 --> 00:23:29,360 creating a chain of islands and 633 00:23:29,461 --> 00:23:30,894 undersea mountains, and that's 634 00:23:30,929 --> 00:23:31,895 what we're seeing in Hawaii 635 00:23:31,930 --> 00:23:38,002 today. 636 00:23:38,069 --> 00:23:39,903 >> This theory was a geological 637 00:23:39,938 --> 00:23:42,273 masterstroke. It didn't just 638 00:23:42,340 --> 00:23:44,842 explain how Hawaii was created, 639 00:23:44,909 --> 00:23:46,377 it also confirmed one of the 640 00:23:46,444 --> 00:23:47,845 most radical theories of the 641 00:23:47,912 --> 00:23:50,014 20th century, the theory of 642 00:23:50,081 --> 00:23:54,385 plate tectonics. 643 00:23:54,452 --> 00:23:56,186 Here, at last, was evidence that 644 00:23:56,254 --> 00:23:58,022 the vast lumbering plates that 645 00:23:58,089 --> 00:24:02,660 made up the Earth were moving. 646 00:24:02,727 --> 00:24:04,528 Tuzo Wilson's hotspot theory 647 00:24:04,562 --> 00:24:06,096 changed our understanding of our 648 00:24:06,164 --> 00:24:08,365 planet forever, but it also left 649 00:24:08,466 --> 00:24:10,801 behind a controversy that still 650 00:24:10,835 --> 00:24:14,805 rages to this day. 651 00:24:14,839 --> 00:24:19,176 How was the hotspot created? 652 00:24:19,244 --> 00:24:20,377 >> (Poland) Ever since scientists 653 00:24:20,445 --> 00:24:22,279 understood that volcanism in 654 00:24:22,380 --> 00:24:23,647 Hawaii was driven by this 655 00:24:23,715 --> 00:24:25,816 hotspot, the question then 656 00:24:25,917 --> 00:24:27,284 became, well what drives the 657 00:24:27,352 --> 00:24:28,452 hotspot? What causes the 658 00:24:28,553 --> 00:24:31,822 hotspot? 659 00:24:31,890 --> 00:24:33,357 >> On the barren slopes of Mauna 660 00:24:33,458 --> 00:24:35,259 Kea on the Big Island, Mike 661 00:24:35,293 --> 00:24:38,529 Poland has found a clue. 662 00:24:38,563 --> 00:24:39,630 >> So what we're looking at here 663 00:24:39,731 --> 00:24:42,099 is what we call a xenolith, it's 664 00:24:42,167 --> 00:24:43,467 basically a foreign piece of 665 00:24:43,535 --> 00:24:45,069 rock that's trapped in this lava 666 00:24:45,103 --> 00:24:46,170 flow. 667 00:24:46,271 --> 00:24:47,738 >> It's where this foreign piece 668 00:24:47,806 --> 00:24:49,907 of rock has come from that's 669 00:24:49,974 --> 00:24:51,608 truly startling. 670 00:24:51,643 --> 00:24:52,710 >> The green mineral you're 671 00:24:52,744 --> 00:24:54,144 seeing in this xenolith here is 672 00:24:54,179 --> 00:24:55,646 a mineral called olivine, and it 673 00:24:55,714 --> 00:24:56,714 really indicates that--that this 674 00:24:56,815 --> 00:24:58,349 chunk here came from someplace 675 00:24:58,450 --> 00:25:01,518 very deep within the Earth. 676 00:25:01,553 --> 00:25:03,187 >> Olivine is usually found 677 00:25:03,254 --> 00:25:04,888 hundreds of miles beneath the 678 00:25:04,923 --> 00:25:07,725 surface. Its presence here is 679 00:25:07,826 --> 00:25:09,326 good evidence that the hotspot 680 00:25:09,361 --> 00:25:10,994 is powered by something deep 681 00:25:11,096 --> 00:25:13,831 within the Earth. And in the 682 00:25:13,898 --> 00:25:16,233 1970s, american geologists 683 00:25:16,334 --> 00:25:17,234 finally came up with a 684 00:25:17,335 --> 00:25:20,070 groundbreaking theory. They 685 00:25:20,138 --> 00:25:21,872 theorized that below the hotspot 686 00:25:21,973 --> 00:25:23,974 lies a plume of hot rock, which 687 00:25:24,042 --> 00:25:25,509 rises up through the Earth's 688 00:25:25,610 --> 00:25:29,246 interior. Two or 300 miles below 689 00:25:29,314 --> 00:25:30,781 the surface, it starts to spread 690 00:25:30,849 --> 00:25:34,385 out, forming a huge dome. The 691 00:25:34,419 --> 00:25:41,425 very top of this is the hotspot. 692 00:25:41,493 --> 00:25:43,127 Scientists called this 693 00:25:43,194 --> 00:25:47,765 phenomenon a mantle plume. 694 00:25:47,832 --> 00:25:49,700 No one really knows how deep it 695 00:25:49,768 --> 00:25:51,969 goes, but some scientists have 696 00:25:52,036 --> 00:25:53,103 come to the extraordinary 697 00:25:53,204 --> 00:25:54,605 conclusion that it may stretch 698 00:25:54,672 --> 00:25:56,240 all the way down to the very 699 00:25:56,307 --> 00:25:59,576 core of our planet. 700 00:25:59,677 --> 00:26:00,944 >> It is possible that the plume 701 00:26:01,012 --> 00:26:02,312 extends all the way down to the 702 00:26:02,414 --> 00:26:04,148 core-mantle boundary, and 703 00:26:04,215 --> 00:26:05,416 frankly, that makes good sense 704 00:26:05,483 --> 00:26:07,284 to me, if you look at the size 705 00:26:07,318 --> 00:26:15,292 of the Hawaiian Island chain. 706 00:26:15,326 --> 00:26:16,827 It's a huge feature, it's been 707 00:26:16,861 --> 00:26:18,195 around for tens of millions of 708 00:26:18,229 --> 00:26:19,863 years. To me, that's not 709 00:26:19,964 --> 00:26:20,964 something that can be explained 710 00:26:21,032 --> 00:26:22,399 by something that's--that's just 711 00:26:22,467 --> 00:26:23,500 near the surface, I think it's 712 00:26:23,568 --> 00:26:25,202 got to be something quite deep 713 00:26:25,236 --> 00:26:27,404 within the Earth. 714 00:26:27,472 --> 00:26:29,239 >> Suddenly, experts realized 715 00:26:29,307 --> 00:26:30,841 plumes were the answer to 716 00:26:30,875 --> 00:26:32,042 hundreds of geological 717 00:26:32,143 --> 00:26:33,310 mysteries, which had long 718 00:26:33,411 --> 00:26:35,312 puzzled science, such as the 719 00:26:35,413 --> 00:26:36,914 existence of Icelandic 720 00:26:36,948 --> 00:26:41,452 volcanoes, the Galapagos 721 00:26:41,519 --> 00:26:44,655 Islands, and the vast 722 00:26:44,722 --> 00:26:48,358 Yellowstone supervolcano. 723 00:26:48,426 --> 00:26:50,093 An investigation, begun in 724 00:26:50,195 --> 00:26:52,329 Hawaii, transformed scientists' 725 00:26:52,363 --> 00:26:54,331 understanding, not just of the 726 00:26:54,365 --> 00:26:56,366 Island chain but of the entire 727 00:26:56,468 --> 00:27:02,539 Planet. 728 00:27:02,640 --> 00:27:04,274 Rock dating and the unusually 729 00:27:04,375 --> 00:27:05,809 straight alignment of the island 730 00:27:05,910 --> 00:27:07,444 chain revealed that the Pacific 731 00:27:07,512 --> 00:27:08,912 Plate is moving over a 732 00:27:08,980 --> 00:27:12,516 stationary hotspot. Olivine rock 733 00:27:12,550 --> 00:27:14,451 erupted on Hawaii's Big Island 734 00:27:14,519 --> 00:27:16,520 shows this hotspot is powered 735 00:27:16,554 --> 00:27:18,689 by a mantle plume originating 736 00:27:18,723 --> 00:27:20,057 from the very bowels of the 737 00:27:20,091 --> 00:27:22,192 Earth. But while the Hawaiian 738 00:27:22,260 --> 00:27:23,827 Islands have been created by 739 00:27:23,895 --> 00:27:25,996 this very hotspot, another, 740 00:27:26,097 --> 00:27:27,965 equally powerful, force is 741 00:27:27,999 --> 00:27:31,615 working to destroy them. 742 00:27:35,614 --> 00:27:37,815 In Hawaii, a strange force is at 743 00:27:37,882 --> 00:27:40,985 work. While the Big Island is 744 00:27:41,019 --> 00:27:42,786 growing by 11,000 square feet 745 00:27:42,821 --> 00:27:44,722 a year, the islands at the 746 00:27:44,789 --> 00:27:46,190 northern end of the chain are 747 00:27:46,258 --> 00:27:49,693 vanishing into the Pacific at a 748 00:27:49,728 --> 00:27:52,696 rate of 2,400 square feet a 749 00:27:52,731 --> 00:27:57,167 year. These islands are 750 00:27:57,235 --> 00:28:00,271 disappearing fast. 751 00:28:00,372 --> 00:28:02,072 Geologists were curious about 752 00:28:02,173 --> 00:28:03,741 what force could cause them to 753 00:28:03,808 --> 00:28:11,548 vanish. 754 00:28:11,650 --> 00:28:13,183 They found their first clue in 755 00:28:13,285 --> 00:28:16,620 early scientific studies. 1950s 756 00:28:16,721 --> 00:28:18,322 underwater sea mapping produced 757 00:28:18,356 --> 00:28:20,057 a wealth of data, and these 758 00:28:20,091 --> 00:28:21,458 results revealed something 759 00:28:21,526 --> 00:28:25,162 completely unexpected. 760 00:28:25,263 --> 00:28:26,530 Heat and pressure from the 761 00:28:26,598 --> 00:28:28,432 hotspot had forced up the 762 00:28:28,533 --> 00:28:30,968 ocean floor, creating a bulge 763 00:28:31,002 --> 00:28:34,538 750 miles long and 500 feet 764 00:28:34,639 --> 00:28:39,043 high. The chain is raised by the 765 00:28:39,110 --> 00:28:40,878 swell, but as the islands move 766 00:28:40,945 --> 00:28:42,413 away from the hotspot, they 767 00:28:42,480 --> 00:28:44,515 slide off the swollen crust, 768 00:28:44,582 --> 00:28:48,852 sinking further and further. 769 00:28:48,920 --> 00:28:50,287 >> Eventually, as they move 770 00:28:50,322 --> 00:28:52,122 northward at about eight to ten 771 00:28:52,157 --> 00:28:53,557 centimeters, that's about three 772 00:28:53,591 --> 00:28:55,659 and a half inches, per year-- 773 00:28:55,694 --> 00:28:58,595 so in, say, another, um, one to 774 00:28:58,663 --> 00:29:00,764 two million years, this island 775 00:29:00,865 --> 00:29:02,866 will probably be as much as 776 00:29:02,934 --> 00:29:05,302 three to 4,000 feet lower, 777 00:29:05,337 --> 00:29:06,737 probably have relatively little 778 00:29:06,771 --> 00:29:09,940 freshwater on it and not be 779 00:29:10,041 --> 00:29:13,677 very inhabitable. 780 00:29:13,778 --> 00:29:15,112 >> The hotspot that created the 781 00:29:15,146 --> 00:29:20,150 islands also seals their fate. 782 00:29:20,218 --> 00:29:21,418 But the islands aren't just 783 00:29:21,486 --> 00:29:24,555 sinking, they're shrinking too. 784 00:29:24,589 --> 00:29:27,057 Erosion is the culprit. It's 785 00:29:27,125 --> 00:29:28,692 slowly destroying the islands, 786 00:29:28,760 --> 00:29:29,960 and nowhere is this more 787 00:29:30,028 --> 00:29:31,495 apparent than on Kauai, the 788 00:29:31,596 --> 00:29:35,599 oldest island of Hawaii. 789 00:29:35,667 --> 00:29:36,934 Here, along the coastline, 790 00:29:36,968 --> 00:29:38,502 intense weathering may have 791 00:29:38,570 --> 00:29:39,603 produced some of the most 792 00:29:39,671 --> 00:29:41,305 breathtaking natural features in 793 00:29:41,406 --> 00:29:43,040 the world, but it is also 794 00:29:43,108 --> 00:29:44,408 evidence of the island's 795 00:29:44,476 --> 00:29:48,212 inherent flaw. And erosion isn't 796 00:29:48,313 --> 00:29:50,414 just taking place at the coast. 797 00:29:50,482 --> 00:29:52,015 It's happening all over the 798 00:29:52,050 --> 00:29:55,753 island. 799 00:29:55,854 --> 00:29:58,222 [birds crying] 800 00:29:58,323 --> 00:30:00,657 Waimea Canyon, Hawaii's grand 801 00:30:00,759 --> 00:30:03,026 canyon, a ten-mile scar through 802 00:30:03,094 --> 00:30:05,829 Kauai's green wilderness. 803 00:30:05,864 --> 00:30:07,765 Over 3,000 feet deep, this 804 00:30:07,866 --> 00:30:09,299 canyon is the most dramatic 805 00:30:09,367 --> 00:30:17,207 example of erosion in Hawaii. 806 00:30:17,308 --> 00:30:18,342 >> If you look up to the east, 807 00:30:18,410 --> 00:30:19,376 you'll see one of the rainiest 808 00:30:19,411 --> 00:30:20,844 places in the world, Mount 809 00:30:20,945 --> 00:30:24,948 Waialeale. Rain flows from that 810 00:30:25,016 --> 00:30:31,088 Mountain down into the canyon. 811 00:30:31,122 --> 00:30:32,756 >> Mount Waialeale receives 812 00:30:32,824 --> 00:30:34,925 over 400 inches of rain every 813 00:30:35,026 --> 00:30:36,560 year, which pours out over the 814 00:30:36,661 --> 00:30:43,267 island, carving out the canyon. 815 00:30:43,301 --> 00:30:44,768 But the islands are made of 816 00:30:44,836 --> 00:30:46,637 basalt lava, one of the hardest 817 00:30:46,671 --> 00:30:50,107 rocks on Earth. How could water 818 00:30:50,175 --> 00:30:53,210 alone be wearing them away? 819 00:30:53,278 --> 00:30:54,945 The answer lies in the canyon's 820 00:30:55,046 --> 00:30:58,382 spectacular red walls. 821 00:30:58,483 --> 00:30:59,716 >> The reddish color is from 822 00:30:59,751 --> 00:31:01,385 the oxidation of the mineral 823 00:31:01,453 --> 00:31:03,554 iron, which makes up about 824 00:31:03,655 --> 00:31:05,389 ten to 12 percent of the lava 825 00:31:05,457 --> 00:31:08,926 rock here. It's very similar to 826 00:31:08,993 --> 00:31:10,994 the rust that forms on your car. 827 00:31:11,029 --> 00:31:12,129 So, literally, we're looking at 828 00:31:12,197 --> 00:31:14,097 a highly rusted landscape, if 829 00:31:14,199 --> 00:31:15,766 you will, which makes it very 830 00:31:15,834 --> 00:31:18,902 soft. So, in a sense, it's, uh, 831 00:31:18,937 --> 00:31:21,004 somewhat rotten. 832 00:31:21,039 --> 00:31:22,573 >> Exposed to water, the high 833 00:31:22,674 --> 00:31:24,107 level of iron in this lava 834 00:31:24,175 --> 00:31:25,943 causes the rock to rust and 835 00:31:26,010 --> 00:31:28,645 crumble. It's the paradox of the 836 00:31:28,713 --> 00:31:30,647 Hawaiian Islands. They're made 837 00:31:30,748 --> 00:31:32,449 of volcanic basalt, one of 838 00:31:32,484 --> 00:31:34,651 nature's hardest rocks, but it's 839 00:31:34,752 --> 00:31:36,753 fatally flawed. 840 00:31:36,855 --> 00:31:38,388 >> This, uh, rock, which, uh, 841 00:31:38,456 --> 00:31:39,990 initially was, uh, very dense, 842 00:31:40,024 --> 00:31:41,191 hard lava you could barely break 843 00:31:41,292 --> 00:31:42,759 with a hammer, we can now 844 00:31:42,827 --> 00:31:44,294 actually pull out pieces with 845 00:31:44,362 --> 00:31:49,399 our hand. 846 00:31:49,467 --> 00:31:51,001 >> Combine this crumbling rock 847 00:31:51,102 --> 00:31:52,002 with some of the highest 848 00:31:52,103 --> 00:31:54,104 rainfall in the world, and the 849 00:31:54,205 --> 00:31:56,273 result is massive erosion over 850 00:31:56,307 --> 00:31:59,009 millions of years. But 851 00:31:59,110 --> 00:32:00,711 scientists knew that erosion 852 00:32:00,745 --> 00:32:02,212 alone couldn't be causing the 853 00:32:02,280 --> 00:32:09,286 islands to disappear. 854 00:32:09,354 --> 00:32:11,121 On the island of Molokai, they 855 00:32:11,189 --> 00:32:12,823 found evidence that vast tracts 856 00:32:12,924 --> 00:32:14,558 of land had disappeared, not 857 00:32:14,626 --> 00:32:16,460 over millions of years, but 858 00:32:16,528 --> 00:32:19,830 overnight. 859 00:32:19,931 --> 00:32:21,798 Satellite images revealed that 860 00:32:21,833 --> 00:32:23,567 Molokai is not like the other 861 00:32:23,635 --> 00:32:25,969 round lands of Hawaii. 862 00:32:26,037 --> 00:32:27,538 >> Something strange happened to 863 00:32:27,605 --> 00:32:28,705 Molokai, it's quite obvious just 864 00:32:28,806 --> 00:32:31,341 by looking at any map. 865 00:32:31,409 --> 00:32:33,443 It's not a round volcano, part 866 00:32:33,511 --> 00:32:34,778 of it is missing. 867 00:32:34,879 --> 00:32:36,513 >> It's a thin strip of land 868 00:32:36,581 --> 00:32:38,715 with sharp cliff edges, shorn 869 00:32:38,783 --> 00:32:42,052 away into steep faces. 870 00:32:42,120 --> 00:32:44,588 At 1,700 feet, these are the 871 00:32:44,656 --> 00:32:47,357 highest sea cliffs in the world. 872 00:32:47,392 --> 00:32:48,926 All the evidence pointed to a 873 00:32:49,027 --> 00:32:51,728 sudden cataclysmic event. 874 00:32:51,763 --> 00:32:53,397 Many theories were put forward, 875 00:32:53,498 --> 00:32:55,265 but it wasn't until the 1980s 876 00:32:55,300 --> 00:32:56,500 that geologists got the 877 00:32:56,568 --> 00:32:57,901 evidence they desperately 878 00:32:57,936 --> 00:33:00,370 needed. After the success of 879 00:33:00,405 --> 00:33:01,905 earlier underwater mapping, the 880 00:33:01,940 --> 00:33:03,941 U.S. Navy returned to Hawaii 881 00:33:04,042 --> 00:33:05,375 with the world's most advanced 882 00:33:05,410 --> 00:33:07,678 sonar system and surveyed the 883 00:33:07,745 --> 00:33:09,479 surrounding waters in incredible 884 00:33:09,547 --> 00:33:11,682 detail. They discovered the 885 00:33:11,749 --> 00:33:13,216 seabed on the island's north 886 00:33:13,284 --> 00:33:15,018 side was littered with gigantic 887 00:33:15,086 --> 00:33:17,487 underwater blocks of land, some 888 00:33:17,589 --> 00:33:18,722 larger than the island of 889 00:33:18,823 --> 00:33:21,224 Manhattan. Geologists took 890 00:33:21,292 --> 00:33:22,859 thousands of samples and 891 00:33:22,927 --> 00:33:24,928 measured the blocks. What they 892 00:33:25,029 --> 00:33:28,031 found was incredible. 893 00:33:28,132 --> 00:33:29,566 These blocks could be fitted 894 00:33:29,634 --> 00:33:30,901 back to the island's steep 895 00:33:30,935 --> 00:33:32,469 cliffs like a giant jigsaw 896 00:33:32,570 --> 00:33:35,839 puzzle. Finally, scientists had 897 00:33:35,907 --> 00:33:37,441 enough evidence to put together 898 00:33:37,475 --> 00:33:40,644 a picture of what had happened. 899 00:33:40,745 --> 00:33:42,379 Radiometric dating confirmed the 900 00:33:42,447 --> 00:33:44,014 age of the blocks and showed 901 00:33:44,082 --> 00:33:45,282 that they were the result of an 902 00:33:45,383 --> 00:33:47,117 event which had taken place over 903 00:33:47,218 --> 00:33:49,753 a million years ago. Geologists 904 00:33:49,854 --> 00:33:51,188 knew there could only be one 905 00:33:51,222 --> 00:33:53,023 explanation - a massive 906 00:33:53,124 --> 00:33:55,292 landslide. 907 00:33:55,393 --> 00:33:56,360 >> One and a half million years 908 00:33:56,394 --> 00:33:58,996 ago, um, there was a very bad 909 00:33:59,030 --> 00:34:02,032 day in the Hawaiian Islands, 910 00:34:02,100 --> 00:34:03,667 the entire north slope of the 911 00:34:03,735 --> 00:34:05,435 island slipped off into the 912 00:34:05,470 --> 00:34:08,572 Ocean, a section 25 miles long 913 00:34:08,640 --> 00:34:09,906 and perhaps as much as a mile 914 00:34:09,941 --> 00:34:12,175 thick, and it did it all at 915 00:34:12,210 --> 00:34:15,345 once. 916 00:34:15,380 --> 00:34:16,913 >> This huge section of the 917 00:34:17,015 --> 00:34:18,649 island crashed into the ocean, 918 00:34:18,716 --> 00:34:20,117 splitting into massive blocks 919 00:34:20,184 --> 00:34:25,822 weighing millions of tons. 920 00:34:25,923 --> 00:34:27,457 The force with which they 921 00:34:27,558 --> 00:34:28,892 crashed into the waves meant 922 00:34:28,926 --> 00:34:30,527 they didn't stop dead but 923 00:34:30,561 --> 00:34:31,995 continued to move along the 924 00:34:32,030 --> 00:34:33,830 ocean floor at an incredible 925 00:34:33,898 --> 00:34:35,365 speed. 926 00:34:35,466 --> 00:34:36,466 >> It was sudden, it was 927 00:34:36,534 --> 00:34:38,435 dramatic, and we know that 928 00:34:38,469 --> 00:34:40,270 because of how far the blocks 929 00:34:40,304 --> 00:34:42,539 went, they--they went down into 930 00:34:42,573 --> 00:34:43,740 this trough around the Hawaiian 931 00:34:43,841 --> 00:34:44,908 Islands and then up the other 932 00:34:44,976 --> 00:34:48,078 side and eventually stopped 933 00:34:48,112 --> 00:34:50,113 about 200 miles away. And for 934 00:34:50,181 --> 00:34:51,915 them to go that far means they 935 00:34:51,983 --> 00:34:54,284 had to be traveling about 150, 936 00:34:54,352 --> 00:34:57,721 160 miles an hour, really fast, 937 00:34:57,755 --> 00:34:59,423 and of course, it's displacing 938 00:34:59,457 --> 00:35:00,924 water while it's doing that, so 939 00:35:00,992 --> 00:35:02,926 you're creating for the Hawaiian 940 00:35:02,994 --> 00:35:04,728 Islands a huge tsunami, a 941 00:35:04,829 --> 00:35:05,929 tsunami that would have--would 942 00:35:05,997 --> 00:35:07,097 have reached to the top of the 943 00:35:07,198 --> 00:35:13,203 cliffs behind me. 944 00:35:13,271 --> 00:35:15,338 >> A landslide on this scale and 945 00:35:15,373 --> 00:35:16,540 at this speed would have 946 00:35:16,641 --> 00:35:18,175 produced one of the most awesome 947 00:35:18,276 --> 00:35:20,110 and deadly waves ever seen on 948 00:35:20,178 --> 00:35:22,379 the planet. 949 00:35:22,447 --> 00:35:23,814 >> The main event was over in 950 00:35:23,915 --> 00:35:27,084 only five minutes, and, uh, and 951 00:35:27,185 --> 00:35:28,518 I'm afraid that, if you saw 952 00:35:28,553 --> 00:35:29,820 that, it would be too late, 953 00:35:29,921 --> 00:35:31,621 because, yeah, you could run as 954 00:35:31,656 --> 00:35:32,989 hard as you like and--and you 955 00:35:33,091 --> 00:35:33,990 wouldn't get away from the 956 00:35:34,092 --> 00:35:35,292 subsequent--the subsequent 957 00:35:35,359 --> 00:35:37,894 tsunami. 958 00:35:37,929 --> 00:35:39,563 >> But what could have caused 959 00:35:39,630 --> 00:35:42,999 such catastrophic land failure? 960 00:35:43,101 --> 00:35:44,735 Geologists look to the youngest 961 00:35:44,802 --> 00:35:46,169 island, the Big Island, for 962 00:35:46,270 --> 00:35:48,905 answers. 963 00:35:49,006 --> 00:35:50,440 Here the island is still 964 00:35:50,541 --> 00:35:52,275 building, just as Molokai once 965 00:35:52,376 --> 00:35:54,111 did, and experts suspect they 966 00:35:54,178 --> 00:35:55,612 will find their answer in the 967 00:35:55,646 --> 00:35:58,081 island's foundations. 968 00:35:58,182 --> 00:35:59,549 >> As the new land builds out, 969 00:35:59,650 --> 00:36:00,984 it's building on sand that's 970 00:36:01,085 --> 00:36:02,719 deposited in front of the lava 971 00:36:02,787 --> 00:36:05,622 flows and so it's very unstable. 972 00:36:05,690 --> 00:36:07,357 And every once in a while, this 973 00:36:07,425 --> 00:36:09,059 material collapses, leaves the 974 00:36:09,093 --> 00:36:10,694 lava unsupported, and it breaks 975 00:36:10,728 --> 00:36:12,262 and it slides down into the 976 00:36:12,363 --> 00:36:13,530 ocean. 977 00:36:13,598 --> 00:36:14,631 >> It was a disturbing 978 00:36:14,699 --> 00:36:17,801 discovery. All Hawaii's islands 979 00:36:17,869 --> 00:36:19,803 were built rapidly and entirely 980 00:36:19,871 --> 00:36:21,905 from lava. They are all based on 981 00:36:21,973 --> 00:36:24,274 the same weak foundations. 982 00:36:24,375 --> 00:36:26,143 And that means a landslide could 983 00:36:26,177 --> 00:36:31,348 strike anywhere. 984 00:36:31,415 --> 00:36:32,816 On the south coast of the Big 985 00:36:32,917 --> 00:36:34,184 Island, there's evidence that 986 00:36:34,252 --> 00:36:36,086 another major landslide could 987 00:36:36,154 --> 00:36:39,523 be about to occur. A huge tear 988 00:36:39,557 --> 00:36:41,258 in the Earth points to where a 989 00:36:41,325 --> 00:36:44,427 4,700 square mile chunk of land 990 00:36:44,462 --> 00:36:46,163 is breaking away from the Big 991 00:36:46,230 --> 00:36:48,365 Island at a rate of four inches 992 00:36:48,432 --> 00:36:52,002 a year. For its size, this is 993 00:36:52,069 --> 00:36:53,970 the fastest moving tract of land 994 00:36:54,071 --> 00:36:56,773 on the planet. Geologists have 995 00:36:56,808 --> 00:36:58,074 calculated that if it were to 996 00:36:58,176 --> 00:36:59,709 fall into the ocean, it could 997 00:36:59,777 --> 00:37:01,278 trigger an Earthquake up to 998 00:37:01,345 --> 00:37:03,814 magnitude seven and unleash a 999 00:37:03,881 --> 00:37:06,683 colossal tsunami. All the cities 1000 00:37:06,717 --> 00:37:08,718 of Hawaii would be swept away as 1001 00:37:08,820 --> 00:37:10,720 a mammoth wave races towards the 1002 00:37:10,822 --> 00:37:17,894 California coast. 1003 00:37:17,995 --> 00:37:19,596 Investigators have discovered 1004 00:37:19,630 --> 00:37:22,866 why Hawaii is disappearing. 1005 00:37:22,900 --> 00:37:24,768 Sonar maps reveal the islands 1006 00:37:24,802 --> 00:37:26,269 are sliding off a swollen 1007 00:37:26,337 --> 00:37:28,772 section of the Earth's crust. 1008 00:37:28,806 --> 00:37:30,440 Kauai's crumbling landscape 1009 00:37:30,541 --> 00:37:32,142 reveals an inherent flaw in the 1010 00:37:32,176 --> 00:37:33,710 islands. They are made of the 1011 00:37:33,778 --> 00:37:35,078 hardest rock on Earth, but 1012 00:37:35,146 --> 00:37:36,813 exposed to water, they rapidly 1013 00:37:36,881 --> 00:37:39,316 break down. And Molokai's 1014 00:37:39,350 --> 00:37:40,884 dramatic cliffs, shorn away 1015 00:37:40,985 --> 00:37:42,586 overnight, are evidence of 1016 00:37:42,620 --> 00:37:46,156 catastrophic landslides. 1017 00:37:46,257 --> 00:37:48,058 Sinking, eroding and crashing 1018 00:37:48,092 --> 00:37:49,793 into the Pacific, eventually, 1019 00:37:49,894 --> 00:37:51,428 even the Big Island will be 1020 00:37:51,495 --> 00:37:53,230 just another underwater mountain 1021 00:37:53,264 --> 00:37:55,765 in the long chain hidden beneath 1022 00:37:55,800 --> 00:37:58,168 the waves. But the story of 1023 00:37:58,269 --> 00:38:00,303 Hawaii is far from over. 1024 00:38:00,371 --> 00:38:01,671 Rumblings from under the sea 1025 00:38:01,739 --> 00:38:03,573 tell scientists a new monster 1026 00:38:03,641 --> 00:38:06,409 may be rising from the waves. 1027 00:38:06,477 --> 00:38:08,278 Now they must venture into one 1028 00:38:08,312 --> 00:38:09,946 of the most hostile environments 1029 00:38:10,047 --> 00:38:12,315 on Earth, where fire meets 1030 00:38:12,383 --> 00:38:13,921 water. 1031 00:38:18,766 --> 00:38:20,200 The story of Hawaii is an 1032 00:38:20,268 --> 00:38:21,601 incredible tale of giant 1033 00:38:21,669 --> 00:38:25,438 volcanoes, unimaginable 1034 00:38:25,506 --> 00:38:28,275 catastrophe and vanishing 1035 00:38:28,309 --> 00:38:30,844 islands, but it doesn't end 1036 00:38:30,912 --> 00:38:33,814 here. Because, only 20 miles off 1037 00:38:33,848 --> 00:38:35,048 the Big Island's beaches, 1038 00:38:35,116 --> 00:38:37,284 something strange is stirring in 1039 00:38:37,318 --> 00:38:42,122 the depths. 1040 00:38:42,190 --> 00:38:44,591 In the 1950s, sea floor surveys 1041 00:38:44,659 --> 00:38:45,959 revealed that an underwater 1042 00:38:46,027 --> 00:38:47,594 volcano sat right on the 1043 00:38:47,662 --> 00:38:50,463 flanks of the Big Island. 1044 00:38:50,498 --> 00:38:51,932 Geologists were intrigued by 1045 00:38:51,999 --> 00:38:53,867 this giant seamount rising up 1046 00:38:53,935 --> 00:38:56,136 two miles from the ocean floor, 1047 00:38:56,204 --> 00:38:59,039 and named it Loihi. Scientists 1048 00:38:59,106 --> 00:39:00,674 were desperate to learn more. 1049 00:39:00,741 --> 00:39:02,108 but it wasn't until 40 years 1050 00:39:02,210 --> 00:39:03,410 later, when the technology 1051 00:39:03,477 --> 00:39:04,778 became available, that they 1052 00:39:04,879 --> 00:39:05,979 were able to dive down and 1053 00:39:06,047 --> 00:39:08,315 investigate the seamount. 1054 00:39:08,349 --> 00:39:09,349 >> (man) Scientists were very 1055 00:39:09,417 --> 00:39:10,317 interested to go down and 1056 00:39:10,418 --> 00:39:12,052 actually see what the situation 1057 00:39:12,119 --> 00:39:14,754 was, so they took the research 1058 00:39:14,789 --> 00:39:16,156 submarine Alvin, which is the 1059 00:39:16,224 --> 00:39:17,791 very famous three-person sub 1060 00:39:17,892 --> 00:39:19,960 that found the Titanic, and they 1061 00:39:20,061 --> 00:39:21,695 went down to the seamount and 1062 00:39:21,796 --> 00:39:24,965 found that there was a huge 1063 00:39:25,032 --> 00:39:26,499 pile of volcanic rocks that were 1064 00:39:26,601 --> 00:39:29,603 all freshly broken. And here's a 1065 00:39:29,670 --> 00:39:30,770 sample, this is a very heavy 1066 00:39:30,872 --> 00:39:32,706 rock, and it's a top of a pillow 1067 00:39:32,773 --> 00:39:34,975 lava. 1068 00:39:35,042 --> 00:39:36,676 >> Pillow lava was evidence of a 1069 00:39:36,711 --> 00:39:44,784 very recent eruption. 1070 00:39:44,852 --> 00:39:46,686 Scientists had believed Loihi to 1071 00:39:46,787 --> 00:39:48,889 be an ancient volcano, extinct 1072 00:39:48,956 --> 00:39:51,124 for thousands of years. But this 1073 00:39:51,158 --> 00:39:52,425 discovery called for some 1074 00:39:52,493 --> 00:39:56,062 radical rethinking. Could Loihi 1075 00:39:56,130 --> 00:40:00,033 be alive and erupting? Experts 1076 00:40:00,067 --> 00:40:01,968 struggled for 11 years to find 1077 00:40:02,069 --> 00:40:04,304 indisputable proof, mapping the 1078 00:40:04,338 --> 00:40:05,939 seamount extensively and taking 1079 00:40:05,973 --> 00:40:08,608 thounds of samples, until, 1080 00:40:08,676 --> 00:40:10,043 finally, they came across the 1081 00:40:10,111 --> 00:40:11,611 piece of evidence they had been 1082 00:40:11,679 --> 00:40:13,413 searching for. 1083 00:40:13,481 --> 00:40:15,515 >> Now it wasn't until 1996 1084 00:40:15,583 --> 00:40:16,850 that, really, the smoking gun 1085 00:40:16,884 --> 00:40:21,288 was discovered. 1086 00:40:21,322 --> 00:40:22,856 In October that year, there was 1087 00:40:22,924 --> 00:40:25,492 a huge number of seismic events 1088 00:40:25,593 --> 00:40:27,060 occurring that the people at the 1089 00:40:27,128 --> 00:40:28,962 volcano observatory discovered, 1090 00:40:29,030 --> 00:40:30,063 but they quickly realized that 1091 00:40:30,131 --> 00:40:31,298 the source of the seismic 1092 00:40:31,332 --> 00:40:32,933 activity was not on the island 1093 00:40:32,967 --> 00:40:35,669 here, it was offshore. They did 1094 00:40:35,770 --> 00:40:36,937 the best estimates they could 1095 00:40:36,971 --> 00:40:38,038 and it all pointed to this 1096 00:40:38,105 --> 00:40:39,239 seamount off the south 1097 00:40:39,307 --> 00:40:40,941 end of the Big Island. 1098 00:40:41,008 --> 00:40:42,876 >> This swarm of earthquakes 1099 00:40:42,944 --> 00:40:44,744 coming from Loihi were the 1100 00:40:44,779 --> 00:40:46,513 largest number ever recorded 1101 00:40:46,580 --> 00:40:49,516 from any Hawaiian volcano. 1102 00:40:49,583 --> 00:40:51,051 Scientists knew they were on the 1103 00:40:51,118 --> 00:40:52,319 verge of an incredible 1104 00:40:52,386 --> 00:40:54,587 discovery. Desperate to witness 1105 00:40:54,655 --> 00:40:55,855 the action as it happened, 1106 00:40:55,923 --> 00:40:57,324 scientists rushed to the heart 1107 00:40:57,391 --> 00:40:59,225 of the activity. 1108 00:40:59,327 --> 00:41:00,226 >> The trick was to get out 1109 00:41:00,328 --> 00:41:01,394 there while the eruption was 1110 00:41:01,495 --> 00:41:07,767 occurring. 1111 00:41:07,868 --> 00:41:09,569 So we went out there, there was 1112 00:41:09,603 --> 00:41:10,937 a tremendous amount of seismic 1113 00:41:11,038 --> 00:41:12,505 activity. From the ship you 1114 00:41:12,573 --> 00:41:13,773 could actually hear the noise of 1115 00:41:13,874 --> 00:41:16,776 the earthquake. 1116 00:41:16,844 --> 00:41:18,578 >> Venturing into the unknown, a 1117 00:41:18,646 --> 00:41:19,946 team from the University of 1118 00:41:20,014 --> 00:41:21,948 Hawaii dived 3,000 feet down 1119 00:41:22,049 --> 00:41:23,583 into this dangerous and 1120 00:41:23,684 --> 00:41:26,686 unpredictable environment. 1121 00:41:26,754 --> 00:41:28,054 >> Everywhere you could see were 1122 00:41:28,122 --> 00:41:32,459 mounds of broken up rock. 1123 00:41:32,493 --> 00:41:34,761 In this murky water was this 1124 00:41:34,862 --> 00:41:37,764 precipice. The top of the 1125 00:41:37,865 --> 00:41:39,933 Seamount had suddenly collapsed 1126 00:41:40,001 --> 00:41:41,568 to create this pit crater that 1127 00:41:41,669 --> 00:41:43,203 was hundreds of feet across and 1128 00:41:43,304 --> 00:41:44,938 hundreds of feet deep, and this 1129 00:41:45,006 --> 00:41:47,007 was the first evidence for 1130 00:41:47,041 --> 00:41:50,410 really active volcanic activity. 1131 00:41:50,478 --> 00:41:52,278 >> Experts had just missed one 1132 00:41:52,313 --> 00:41:53,947 of the most violent eruptions 1133 00:41:54,048 --> 00:41:56,483 Hawaii had ever seen, but, as 1134 00:41:56,517 --> 00:41:58,585 the dust settled, they were able 1135 00:41:58,652 --> 00:42:01,955 to survey the aftermath. 1136 00:42:02,023 --> 00:42:03,590 Lava had poured out of the 1137 00:42:03,657 --> 00:42:05,759 volcano, draining the summit and 1138 00:42:05,826 --> 00:42:13,566 causing it to collapse. 1139 00:42:13,634 --> 00:42:15,468 The team finally had proof that 1140 00:42:15,503 --> 00:42:17,670 Loihi was an active volcano, 1141 00:42:17,738 --> 00:42:19,572 which will continue to erupt and 1142 00:42:19,640 --> 00:42:21,408 grow until it forms a new 1143 00:42:21,475 --> 00:42:23,843 Island, the next in the Hawaiian 1144 00:42:23,944 --> 00:42:28,314 Chain. 1145 00:42:28,382 --> 00:42:29,482 >> The assumption was there had 1146 00:42:29,583 --> 00:42:31,117 to be another volcano coming up 1147 00:42:31,185 --> 00:42:33,386 one of these days. No one 1148 00:42:33,454 --> 00:42:35,221 knew whether that was gonna 1149 00:42:35,289 --> 00:42:36,856 happen in our lifetime or not, 1150 00:42:36,924 --> 00:42:39,059 but it's very rewarding for the 1151 00:42:39,126 --> 00:42:40,560 scientists to realize that now 1152 00:42:40,628 --> 00:42:42,395 the next volcano in the sequence 1153 00:42:42,463 --> 00:42:44,664 has been discovered - Loihi is 1154 00:42:44,732 --> 00:42:47,367 apparently it. 1155 00:42:47,401 --> 00:42:49,235 >> As lava continues to spew 1156 00:42:49,303 --> 00:42:51,538 from its submerged summit, Loihi 1157 00:42:51,572 --> 00:42:53,373 will build until it rises out of 1158 00:42:53,474 --> 00:42:56,443 the Pacific. The Pacific plate 1159 00:42:56,477 --> 00:42:57,844 will shift, carrying the Big 1160 00:42:57,945 --> 00:42:59,846 Island off the hotspot, and 1161 00:42:59,947 --> 00:43:01,648 Loihi will take its place at the 1162 00:43:01,715 --> 00:43:05,919 head of the Hawaiian chain. 1163 00:43:05,986 --> 00:43:07,654 Experts had studied the ancient 1164 00:43:07,755 --> 00:43:09,255 Islands of Hawaii for hundreds 1165 00:43:09,290 --> 00:43:11,124 of years, theorizing about how 1166 00:43:11,192 --> 00:43:13,293 they were created. But they 1167 00:43:13,394 --> 00:43:14,661 never imagined they would have 1168 00:43:14,762 --> 00:43:16,196 the opportunity to witness it 1169 00:43:16,297 --> 00:43:19,999 for themselves. 1170 00:43:20,034 --> 00:43:23,002 >> Loihi provides us with a real 1171 00:43:23,104 --> 00:43:25,472 unique laboratory, it gives us a 1172 00:43:25,539 --> 00:43:26,840 window back into the past. 1173 00:43:26,941 --> 00:43:28,741 This is our one chance to see 1174 00:43:28,843 --> 00:43:30,577 how it worked before the islands 1175 00:43:30,644 --> 00:43:35,915 reached the surface. 1176 00:43:36,016 --> 00:43:37,650 >> Reviewing all the evidence, 1177 00:43:37,751 --> 00:43:39,752 investigators finally understand 1178 00:43:39,820 --> 00:43:41,287 how the Hawaiian chain was 1179 00:43:41,388 --> 00:43:44,390 created. Gravity readings taken 1180 00:43:44,458 --> 00:43:46,392 in the 1930s show that the Big 1181 00:43:46,460 --> 00:43:49,028 Island is 140 times bigger than 1182 00:43:49,096 --> 00:43:50,730 Mount Everest. Further 1183 00:43:50,798 --> 00:43:52,432 investigation reveals that it is 1184 00:43:52,466 --> 00:43:54,567 made entirely from basalt lava 1185 00:43:54,635 --> 00:43:58,204 from five volcanoes. Rocks 1186 00:43:58,272 --> 00:44:00,006 created deep underground are 1187 00:44:00,074 --> 00:44:01,908 found within the lava and show 1188 00:44:02,009 --> 00:44:03,543 the island's volcanoes are 1189 00:44:03,577 --> 00:44:05,178 fueled by something from deep 1190 00:44:05,212 --> 00:44:07,013 within the Earth, a mantle 1191 00:44:07,081 --> 00:44:10,250 plume. But high levels of iron 1192 00:44:10,284 --> 00:44:12,385 in Hawaii's basalt lava cause 1193 00:44:12,453 --> 00:44:14,754 the islands to crumble. And the 1194 00:44:14,822 --> 00:44:16,256 steep cliffs of Molokai are 1195 00:44:16,290 --> 00:44:20,293 evidence of mega landslides. 1196 00:44:20,361 --> 00:44:22,428 Underwater lava is proof that a 1197 00:44:22,463 --> 00:44:24,731 new volcano is stirring - the 1198 00:44:24,832 --> 00:44:26,266 next island in the chain that 1199 00:44:26,367 --> 00:44:27,834 will eventually emerge from 1200 00:44:27,902 --> 00:44:32,639 beneath the waves. 1201 00:44:32,740 --> 00:44:34,741 Hawaii's dramatic cycle of birth 1202 00:44:34,808 --> 00:44:36,709 and death is more than just a 1203 00:44:36,744 --> 00:44:38,611 geological wonder. It's 1204 00:44:38,646 --> 00:44:40,246 transformed geologists' 1205 00:44:40,281 --> 00:44:41,814 understanding of the entire 1206 00:44:41,815 --> 00:44:42,815 planet. 1207 00:44:43,616 --> 00:44:46,616 On Hawaii we can see for ourselves 1208 00:44:47,017 --> 00:44:49,217 how the Earth is made.